Means for computing circumferences or fractions thereof.



L. J. R. HOLST.

MEANS FOR COMPUTING CIRCUMFERENCES 0R FRACTIONS THEREOF.

APPLICATION FILED luNE 110, 1910.

1,148,588, Patented Aug. s, 1915.

2 SHEETS-SHEET 1.

COLUMBIA PLANOGRAPH co.. WASHINGTON, D. c.

L. l. R. HGLST.

MEANS FoR coMPUTlNG cmcuMFERENcEs on FR-AcloNs THEnEoF.

APPLICATION FILED JUNE l0, $910.-

Patented Aug. 3, 1915.

2 SHEETS-SHEET 2.

WITNESSES:

ATTUHNE Y nnrr LOUIS J. R. HOLST, OF NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGNMENTS, TO LTI-IOTEX CORPORATION, OF NEW YORK, N. Y., A CORPORATION'OF NEW YORK.

MEANS FOR COMPUTING CIRCUMFERENCES OR FRACTIONS THEREOF.

Specification of Letters Patent.

Patented A1110'. 3, 1915.

Application led. .Tune 1D, 1910. Serial No. 566,254.

To all whom it may concern:

Be it known that 1, Louis J. R. HoLs'r, a citizen of the United States, residing in the borough of Brooklyn, city of New York, county of Kings, and State of New York, have invented certain new and useful 1mprovements in Means for Computing Circumferences or Fractions Thereof, of which the following is a specification.

This invention relates to devices for computing circumferences or fractions thereof, and the present embodiment of the invention has been found especially useful for determining the proper height of a design to be reproduced a number of times on a printing surface from which the reproductions are transferred to a metal roller for printing purposes.

Inasmuch as the present embodiment of the invention was particularly gotten up for this use, 1 will describe its construction and operation as actually used in determining the desired height of designs to be transferred to such rollers. These rollers are used for printing continuous or disconnected designs on textile fabric, wall paper, etc., for which purpose it is necessary that the design as a whole which is to be formed on the metal roller, must completely cover the surface of the roller with the ends of the design exactly meeting and registering, so that the design will appear continuous when printed from the roller. One method now known of producing designs on such a roller, is to take a unit of the selected design and reproduce it photographically 'a number of times on adjacent portions of a sensitized surface so as to form, 'when the plate is developed, a complete design of a number of f reproductions of suchy unit. F rom this plate a zinc plate may be made up and properly etched, either of the same size as the developed photographic Plate, or of a different size, the zinc plate being of a length equal to the circumference of the roller on which the design is to`- be transferred. TheV design is then transferred from the zinc plate by inking the plate and rolling the roller upon the same. lnasmuch as it is necessary for the ends of the design to meet and register within one or two thou* sandths of an inch, it is important that'the size of the stepped-up unit design should be accurately determined, and this device is useful in computing the size of such stepped-up designs.

l In practice, it is desirable, for purposes of economy, to step up the design in a size smaller than the size of the design as transferred upon the roller, and to subsequently enlarge the design to the size which it is desired to produce it in. One known prac tice is to step up the designs in two-thirds of their size as subsequently transferred to the roller; and the present embodiment of my invention is one in which the designs may be computed in this size.

The invention will be more readily understood from the following description taken in connection with the accompanying drawings, in which- Figure 1 represents a front view of the device; Fig. 2 a vertical sectional view; Fig. 3 a horizontal sectional view through the lower end of the device; Fig. e is an enlarged view of the Vernier; and Fig. 5 is a detail end view of the base.

The device consists of a pair 0f compass legs 10 and 11, the lower end of the latter being pivoted on a stud 12 projecting from the lower end of the frame 13 while its upper end is pivoted. by means of the pin 14C to the coperating leg 10.

The lowerv end of the leg 10 is pivoted to a block 15 by means of a pin 16, and this block slides in guideways 17 at each side of a slot 18 in the lower end of the frame 13.

The block 15 is regulated in its movements by a screw 19 having the thumb wheel 20 at its outer end. The inner end of the pivot 14C is provided with a convex head 22 which bears against the upper end of the frame and partly relieves the lower pivots from unnecessary strain.

Located above the block 15 is a scale 23 vdivided into 80 even divisions while the block itself carries a scale 24k, divided into 25 parts and constitutes in conjunction with the scale 23 a Vernier reading to 1/1000.

The diameters of the rollers used in the above referred to process are measured and indicated by means of the ordinary standard sliding micrometer calipers; but so far as my present invention is concerned in its broad aspect, these diameters may be measured and indicated by any suitable means and scales. In the present form of my invention, the scale 23 is graduated to read in fractions ofY circumferencesthe diameters of which correspond to the divisions of the regular standard micrometer scales used in measuring the diameters of the rollers; that is, the divisions on this scale 23, while corresponding numerically to those of the micrometer scale, are a fraction of a times the divisions on the micrometer' scaleused in measuring the diameters of the rollers,

so that when the diameter of the roller is measured with a sliding micrometer and its reading, which we will say is three and a half, is reproduced upon the scale 23, the scale 23 will indicate on this instrument a fraction of the circumference corresponding to the diameter three and a half, as indicated on the regular sliding micrometer. For instance, if, as in the present form of my invention, the scale 23 is graduated in divisions of one-third of a times the divisions of the diameter-measuring scale, if the diameter-measuring scale indicates a 3 1/2 inch diameter and the scale of my device is set at the 3 1/2 mark, the distance between the points 12 and 16 will be equal to one-third of the circumference of a roller the diameter'of which is 3 1/2 inches.

The feature of making the scale to read in fractions of the circumference of the roller is useful in computing the height of designs for the purpose of stepping them up in a reduced size, as will hereinafter appear, but it'does not alter the principle of operation of the device to have the scale 23 graduated in units of aD instead of in units of a fraction of aD, since the reduction may be obtained by properly numbering the scales along the legs 10 and 11 from which the height of designs is computed, as will now be described.

. The center lines of both legs 10 and 11 are provided with scales 25 which are graduated and numbered from 3 to 20, the graduation being in fractions of the length of the legs, each graduation being placed at a point representing a definite fraction of the distance along the legs between the point 14 and the points 12 and 16 at the free extremities of the legs. In the present embodiment of the invention, which is to be used in determining the height of designs two-thirds of their final size as transferred to the roller, each graduation is numbered double the fraction of the distance that it actually represents along the legs, so as to give the proper computation in connection with the one-third size scale 23 for a twothird size image desired. For instance, if the divisions of scaleV 23 had been in '1c times the divisions of the micrometer scale for measuring diameters instead of a constant times a: times these divisions and it were desired to compute the actual height of an image four of which were to exactly meet around the roller, after setting the scale 23 corresponding tothe diameter. of the roller, the height of the image would be computed by measuring the Vdistance between two points each one-fourth of the waydown the legs 10 and 11 from their hinged point; but since the divisions of the scale 23 are in, one-third of a times the scale of the diameter-measuring instrument, and since it is desired toV compute the height of the unit designs in two-thirds the size in which they are to be transferred, it is necessary to double the numbers along the scales of the legs to increase the otherwise one-third size totwo-thirds. For example, the points 4 on Vthe scales of legs 10 and 11 are exactly mid-way between point 14 and points 16 and 12, thereby dividing the scale into two equal parts, and the distance between points 4v and 4 is one-half the distance between the points 12 and 16; so that if the scale 23 had been graduated in units of a times the diameter of the roller instead of one-third 7c times the diameter, the points 4 would have been indicated as points 2, indicating the height of the design two of'which would completely encircle the roller; lbut since the size in which the design is to be stepped and repeated isto be-two-thirds of the size in which it is to be applied to the roller, it is found more convenient to make the computation by making the divisions of scale 23 one-third 1c times the divisions of the diameter-measuring scale, and then doubling the value of the indicating numerals along the scales of the legs so as to correctly indicate the desired height of the image which would otherwise be on a one-third scale instead of a two-thirds scale.

In practice, rollers vary from 3-1/2 to 5-1/2 iny diameter. When therefore, the zero of the vernier is set to the 3-1/2 .mark on the scale, it brings the centers 12 and 16 to adistance of 3.665 or a distance equal tov 1/3 of the circumference of a 3-1/2 roller. When at the maximum mark on the scale, it brings the centers 12 and 16, 2.094 farther apart, which represents the distance of 1/3 the circumference of a 5-1/2 roller.

The mannerV of computing the desired fractions of a circumference with the device herein described, is as follows: If it is desired to place a design upon the roller, which design is to comprise four repetitions of the unitv design in vertical alinement or around the circumference of the roller, and if itis desired to step and repeat the design in a this device. A reading of the scale of the micrometer is observed and the scale 23 of this device is set to correspond to the reading on the micrometer caliper, at which setting the distance between the points 16 and 12 will be equal to 1/3 of E times the diameter of the roller, and the distance between the points I on the scales of the leg will be twice one-fourth of this distance, i. e., twice one-fourth of the distance 1/3 11:1):1/6 al), which is the proper height for each of the four images. If it were desired to place six images around the circumference of the roller, the height of each image would be equal tothe distance between the points 6 6 on the legs, etc. It will thus be seen that by the proper graduation of the scales 23 and 25, or either of them, the circumference or any desired fraction of a circumference may be readily computed.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

l. In a. circumference computing device, the combination of a support, a pair of legs pivoted together at one of their extremities, means pivotally connecting the other extremity of one of said legs to the support, a screw connected to the other leg to move the same for varying the distance between the legs, means for guiding said leg in its movements to cause a point at the lower extremity of said leg to move in a straight line causing the other leg to swing about its pivot on the support, and a scale operatively related to the screw-operated leg along the path of movement of said point for determining the setting of the legs, said scale reading in units of circumferences and each leg being provided with a scale graduated in fractions 0f its length for computing fractions of the distances between the legs as indicated on the first scale.

2. In a circumference computing device, the combination of a support, a pair of legs pivoted together at one of their extremities, means pivotally connecting the other extremity of one of said legs to the support, a straight guideway for guiding the corresponding extremity of the other leg, a block movable on said guideway and pivotally connected with the extremity of said last leg, a screw for moving the block along the guideway, and a scale operatively related to the guided extremity of said leg for determining the setting of the legs, the divisions of the scale being a times or a constant multiplied by 7c times of the corresponding divisions of a scale for indicating diameters, each leg being provided with a scale graduated in fractions of its length for computing fractions of the distances indicated on the first scale.

In witness whereof, I have hereunto set my hand this 4th day of May, 1910.

LOUIS J. R. IIOLST.

Copies of this patent may be obtained for ve cents each, by adressing the Commissioner of Patents, Washington, D. C. 

